In fact, the method is very simple, but probably because these friends just started programming soon, temporarily did not find a way.
Here's a brief introduction to using C # to accomplish this task.
First, I'll introduce you to save the file to the database.
Save the file to the database, in effect, after converting the file into a binary stream, save the binary stream to the corresponding field in the database. The data type for this field in SQL Server is image, which is the OLE object in Access.
Copy Code code as follows:
Save files to SQL Server database
FileInfo fi=new FileInfo (fileName);
FileStream Fs=fi. OpenRead ();
Byte[] Bytes=new Byte[fs. Length];
Fs. Read (Bytes,0,convert.toint32 (FS). Length));
SqlCommand cm=new SqlCommand ();
Cm. CONNECTION=CN;
Cm.commandtype=commandtype.text;
if (CN. State==0) cn. Open ();
cm.commandtext= "INSERT INTO" +tablename+ "(" +fieldname+ ") VALUES (@file)";
SqlParameter spfile=new SqlParameter ("@file", sqldbtype.image);
Spfile.value=bytes;
Cm. Parameters.Add (SpFile);
Cm. ExecuteNonQuery ()
Save a file in an Access database
FileInfo fi=new FileInfo (fileName);
FileStream Fs=fi. OpenRead ();
Byte[] Bytes=new Byte[fs. Length];
Fs. Read (Bytes,0,convert.toint32 (FS). Length));
OleDbCommand cm=new OleDbCommand ();
Cm. CONNECTION=CN;
Cm.commandtype=commandtype.text;
if (CN. State==0) cn. Open ();
cm.commandtext= "INSERT INTO" +tablename+ "(" +fieldname+ ") VALUES (@file)";
OleDbParameter spfile=new OleDbParameter ("@file", oledbtype.binary);
Spfile.value=bytes;
Cm. Parameters.Add (SpFile);
Cm. ExecuteNonQuery ()
Save client files to database
sql= "Update t_mail set attachfilename= @attachfilename, attachfile= @attachfile where mailid=" +mailid;
mycommand = new SqlCommand (sql, New SqlConnection (ConnStr));
String path = Fl_name. Postedfile.filename;
String Filename=path. Substring (path. LastIndexOf ("\") +1,path. Length-path.lastindexof ("\")-1);
MYCOMMAND.PARAMETERS.ADD ("@attachfilename", SqlDbType.VarChar);
mycommand.parameters["@attachfilename"]. Value=filename;
MYCOMMAND.PARAMETERS.ADD ("@attachfile", sqldbtype.image);
Stream FileStream = Fl_name. Postedfile.inputstream;
int intfilesize = Fl_name. Postedfile.contentlength;
byte[] filecontent = new Byte[intfilesize];
int intstatus = FileStream.Read (filecontent,0,intfilesize); File read to filecontent array
mycommand.parameters["@attachfile"]. Value= ((byte[]) filecontent);
Filestream.close ();
MyCommand.Connection.Open ();
Mycommand.executenonquery ();
MyCommand.Connection.Close ();
FileName in code is the full name of the file, TableName is the name of the table to be manipulated, FieldName is the name of the field where you want to save the file.
The two pieces of code are actually the same, but the database of the operation is different and the objects used are different.
Then, talking about reading the file from the database, only read from SQL Server.
Copy Code code as follows:
SqlDataReader Dr=null;
SqlConnection objcn=new SqlConnection ();
Objcn.connectionstring= "Data source= (local); User Id=sa; Password=;initial Catalog=test ";
SqlCommand cm=new SqlCommand ();
Cm. CONNECTION=CN;
Cm.commandtype=commandtype.text;
cm.commandtext= "Select" +fieldname+ "from" +tablename+ "where id=1";
dr=cm. ExecuteReader ();
Byte[] File=null;
if (Dr. Read ())
{
File= (byte[]) dr[0];
}
FileStream FS;
FileInfo fi=new System.IO.FileInfo (fileName);
Fs=fi. Openwrite ();
Fs. Write (file,0,file.length);
Fs. Close ();
The above code reads the file saved in the database and saves the file specified by filename.
When using the above code, don't forget to add System.Data.SqlClient and System.IO references.
Modify:
The code to read the following section of the file
Copy Code code as follows:
FileStream FS;
FileInfo fi=new System.IO.FileInfo (fileName);
Fs=fi. Openwrite ();
Fs. Write (file,0,file.length);
Fs. Close ();
Amended to
FileStream fs=new FileStream (filename,filemode.createnew);
BinaryWriter bw=new BinaryWriter (FS);
Bw. Write (file,0,file.length);
Bw. Close ();
Fs. Close ();
